Kumamoto Kensuke, Ishida Hideyuki, Suzuki Okihide, Tajima Yusuke, Chika Noriyasu, Kuwabara Koki, Ishibashi Keiichiro, Saito Katsuharu, Nagata Koji, Eguchi Hidetaka, Tamaru Junichi, Iwama Takeo
Department of Digestive Tract and General Surgery, Saitama Medical Center, Saitama Medical University, Saitama, 350-8550, Japan.
Department of Organ Regulatory Surgery, Fukushima Medical University, 1 Hikarigaoka, Fukushima, 960-1295, Japan.
Surg Today. 2016 Jun;46(6):713-20. doi: 10.1007/s00595-015-1232-1. Epub 2015 Aug 7.
The aim of this study was to investigate the prevalence of Lynch syndrome among Japanese patients with surgically resected colorectal cancer at a single institution.
Of 616 colorectal cancer patients who underwent surgical operation in our institution from January 2005 to August 2010, immunohistochemistry analyses for mismatch repair proteins (MLH1, MSH2, MSH6, and PMS2) and microsatellite instability (MSI) testing for surgically resected, formalin-fixed paraffin-embedded colorectal cancer specimens from 138 colorectal cancer patients under 60 years of age were undertaken. Hypermethylation of the MLH1 promoter and BRAF mutation were analyzed where necessary.
Seven patients were identified as candidates for genetic testing by mismatch repair protein loss (n = 7) or MSI-H (n = 6). Methylation of MLH1 was detected in one case. Three patients were diagnosed with Lynch syndrome, comprising 2.2 % of the total colorectal cancer patients younger than 60 years of age.
The prevalence of Lynch syndrome among hospital-based diagnosed cancer patients may therefore be lower than expected in Japan compared with Western populations.
本研究旨在调查在一家机构接受手术切除的日本结直肠癌患者中林奇综合征的患病率。
对2005年1月至2010年8月在本机构接受手术的616例结直肠癌患者，对138例60岁以下结直肠癌患者手术切除的、福尔马林固定石蜡包埋的结直肠癌标本进行错配修复蛋白（MLH1、MSH2、MSH6和PMS2）免疫组化分析及微卫星不稳定性（MSI）检测。必要时分析MLH1启动子的高甲基化和BRAF突变。
7例患者因错配修复蛋白缺失（n = 7）或微卫星高度不稳定（MSI-H，n = 6）被确定为基因检测候选对象。1例检测到MLH1甲基化。3例患者被诊断为林奇综合征，占60岁以下结直肠癌患者总数的2.2%。
因此，与西方人群相比，在日本基于医院诊断的癌症患者中林奇综合征的患病率可能低于预期。
